(a) Field of the Invention
A Charging Circuit suitable for Broad Voltage Changing Range and of the type of temperature detection automatic cutoff and of Transient Status Maintaining, composed of Transient Maintaining Ckt. suitable for Broad Voltage Range and Negative Temperature Coefficient Resistor Elements serving to verify the temperature of rechargeable cells, such that once the cell is charged to saturation and the temperature of the rechargeable cell rises to a predetermined level, the Negative Temperature Resistor Element will reduce its resistance in response, and that in turn will cutoff the Ckt. automatically, switch to a small current charging status, and the charging status will be maintained once the resistance of the Negative Temp. Coefficient Resistor Element reverts to increase should the temp. of the cell that is being charged go down, or should voltage fluctuation remain within a predetermined power supply voltage level, and the Circuit will reset itself once the rechargeable cell is removed or the power supply suspended.
(b) Description of the Prior Art
As is well known in the profession, conventionally a Charging Ckt. of the Automatic Cutoff and Transient Status Maintaining Type relies on Voltage or Current Detector composed of electronic elements to charge Rechargeable Cells incorporating Temp. Control Switches which, on sensing that there is a rising in temp. as a result of the rechargeable cell reaching saturation, will cause the charging unit to turn to feed a smaller current to the rechargeable cell, whereby the charging function is maintained all the while, a major shortcoming with such conventional Charging Ckt. of the Automatic Cutoff and Transient Status Maintaining Type is that it involves lots of electronic components built on a complicated structure necessitating expensive costs, and most regrettably, low reliability.